The people the article quoted as "left" like Stoller are really not left, and the whole anti-left felt more like a unnecessary strawman label and definite turn off for me reading it. I would characterize Stoller as an independent anti-monopolist - not really on the right or left spectrum at all politically. Unless the right is now pro-monopoly.
He’s specifically talking about Zephyr Teachout. Her work is specifically in anti-monopoly stuff.